There is known an imaging apparatus including an image sensor provided with a three-color (RGB) filter for capturing full-color images. It is known that the gradient information of images is acquired to detect various information from the captured images and to perform various processing of the images. In the conventional imaging apparatus, the number of bands of color filter is small, thus the sample density of image signal components corresponding to each band is relatively high, and the accuracy of the gradient information based on interpolation images produced by color interpolation is sufficiently high.
To provide a faithful color reproduction of an object, a multiband imaging has received an attention. For multiband imaging, photographing with a plurality of cameras or several times of photographing may be performed. However, for such a multiband imaging, a dedicated photographing system has been needed. Thus, there has been suggested that, by using a single-chip multiband image sensor where color filters of four or more bands are arranged, a multiband imaging is performed by taking one photograph with one imaging apparatus (see Patent Literature 1).